This invention generally relates to telecommunications systems and more particularly to virtual bearer high-speed communication channel-to-device interfaces.
In telecommunications networks, multiple communication channels, sometimes referred to as xe2x80x9cbearer channelsxe2x80x9d are multiplexed onto high-speed telecommunications channels. For example, a number of 64 kilobit per second (xe2x80x9ckbpsxe2x80x9d) channels, which may have a DS0 format, can be multiplexed onto a single T1 span. Multiple T1s may, in turn, be multiplexed onto an OC3/STS-3 high-speed optical communications channel.
The STS format is the basic building block of SONET optical interfaces, where STS stands for xe2x80x9cSynchronous Transport Signal.xe2x80x9d The basic SONET building block is the STS-1 signal, which has a rate of 51.84 Mbps. STS consists of two parts, the STS payload and the STS overhead. The STS payload carries information, whereas the STS overhead carries the signaling and protocol information. The STS overhead allows communication between intelligent nodes on the network, permitting administration, surveillance, provisioning and control of a network from a central location.
By using this high-speed multiplexing scheme, very high-bandwidth data communication channels, such as fiber-optic communication channels, may be used effectively for carrying vast quantities of data over great distances. The disadvantage of this approach is that once these many data communication channels are multiplexed onto a single high-speed communication channel, it has been difficult to access and process the original bearer channels contained within the high-speed data communication channel. For example, there may be instances where processing of the single bearer channel carried on an OC3 data communication channel is desired by an application such as a Voice Response Unit (xe2x80x9cVRUxe2x80x9d).
In the past, when the processing of individual data communication channels or voice channels has been desired (within an OC3 high-speed communication channel or the like), an Add-Drop Multiplexer (xe2x80x9cADMxe2x80x9d) or a series of them have been provided to break down the high-speed communication channel into its constituent bearer channels. These bearer channels can then be connected to the application of interest. The connections to the applications through the bearer channels are configured in a relatively fixed fashion, as the connections are formed by programming the ADM to permanently or semi-permanently connect a certain bearer channel to a certain application.
The present invention provides a system and method by which sub-signals, sometimes specifically known as bearer channels, within communication signals can be directly accessed without completely breaking down the communication signal into its constituent parts. Furthermore, the present invention provides a flexible approach whereby individual bearer channels can be accessed and whereby the particular bearer channel accessed can be easily changed.
An embodiment of the invention allows applications to interface with SONET transmission devices and distribute all the data elements from a SONET signal to a bus structure. This bus structure makes the data elements available to applications requiring this data. Also provided is the ability to insert data back to the original timeslot or other timeslots on the bus structure. Data that is not required by applications on this device will be passed to other applications or to the output side of the application-to-device interface. The device interface can restructure the data into a SONET structure for transmission to another like device either locally or remotely, giving other like or unlike applications access to the SONET data in the same manner. This interface will synchronize on the header contained, for example, in a standard SONET STS-1 signal or other higher-level signal to start or restart a data sorting process which will distribute the data at the DS0 level or another lower level to a bus structure in a defined manner. The bus structure could be thirty-two 8 MHz data streams, or it could be another bus architecture. Particularly, the bus structure might be adapted for the specific speed of the high-speed communications channel to which this interfacing is desired.
In one embodiment, for example, the system can be reconfigured under control of a telecommunications resource manager, which would preferably control to which application a particular bearer channel might be connected. For example, if a caller would make a call to a certain phone number, and if that call was contained within a high-speed communications channel, a resource manager would preferably be able to connect applications directly to that caller""s bearer channel.
By reducing or eliminating the necessity for ADMs, large bandwidth, high-speed, communications signals can be implemented in a wider range of applications. This increase in flexibility to use such large signals comes from being able to connect an application directly to bearer channels, which are the sub-signals within the larger bandwidth communication signal. By this improvement, telecommunications service providers can reduce the cabling that has been necessary to access individual bearer channels through ADMs and can also reduce the number of telecommunications equipment racks at network interface points and other points. With these improvements, the overall costs of interfacing to a high-speed telecommunications network are much reduced.